The synthesis and processing of nuclear and cytoplasmic transfer RNA (tRNA), ribosomal RNA (rRNA) and messenger RNA (poly(A)RNA) will be studied in L1210 and Ehrlich ascites cells. The effects of the antimetabolites: 5-fluorouracil, 5-azacytidine, dihydro-5-azacytidine, sangivamycin, and xylosyladenine will be examined on the methylation and synthesis of rRNA, tRNA and poly(A)RNA. 5-Azacytidine and 5-fluorouracil are believed to also exert their antitumor effects through their incorporation into mRNA. This hypothesis will be tested by quantitative and qualitative assessment of the capacity of polysomal poly(A)(RNA) from Ehrlich ascites cells to code for proteins in heterologous cell-free translation systems derived from wheat germ extracts and reticulocyte lysates. These studies will include analyses of the drug-modified poly(A)RNA by agarose gel electrophoresis, and analysis of translation products by polyacrylamide slab gel electrophoresis and autoradiography.